Method and apparatus for constructing subterranean structures

ABSTRACT

THE INVENTION RELATES TO A METHOD FOR EXCAVATING CAVITIES IN THE CONSTRUCTION OF SUBTERRANEAN STRUCTURES SUCH AS TUNNELS WHERE PILOT TUNNELS AE DRIVEN WITHIN THE CROSS-SECTION OF A MAIN TUNNEL TO BE FORMED, PERIPHERAL CAVITIES ARE FORMED BETWEEN THE PILOT TUNNELS, CONCRETE IS POURED INTO THE PERIPHERAL CAVITIES TO FORM THE MAIN TUNNEL LINING, AND THE EARTH BETWEEN THE PILOT TUNNELS THEN EXCAVATED. THE PARTIAL PERIPHERAL CAVITIES ARE FORMED BY MOVING A CUTTING TOOL BACK AND FORTH THROUGHOUT THE CROSS-SECTIONAL PERIPHERAL PATH OF THE MAIN TUNNEL AND ADVANCING THE CUTTING TOOL LONGITUDINALLY OF THE TUNNEL.

Nov. 2, 1971 A. PH. EBER E AL METHOD AND APPARATUS FOR CONSTRUCTING SUBTERRANEAN STRUCTURES Filed Sept. 18., 1969 2 Sheets-Sheet 1 Nov. 2, 1971 P EBER ETAL 3,616,650

METHOD AND APPARATUS FOR cons'mucwme SUBTERRANEAN STRUCTURES Filed Sept. 18, 1969 2 Sheets-Sheet 2 United States Patent 3,616,650 METHOD AND APPARATUS FOR CONSTRUCTING SUBTERRANEAN STRUCTURES Arnold Ph. Eber, Munich, Pasing, and Johann A. Heilbrunner, Munich, Solln, Germany, assignors to Alfred Kunz & Co., Munich, Germany Filed Sept. 18, 1969, Ser. No. 859,098 Claims priority, application Germany, Jan. 27, 1969, P 19 03 911.3 Int. Cl. E01g 3/04 US. CI. 6142 4 Claims ABSTRACT OF THE DISCLOSURE The invention relates to a method for excavating cavities in the construction of subterranean structures such as tunnels Where pilot tunnels are driven within the cross-section of a main tunnel to be formed, peripheral cavities are formed between the pilot tunnels, concrete is poured into the peripheral cavities to form the main tunnel lining, and the earth between the pilot tunnels then excavated. The partial peripheral cavities are formed by moving a cutting tool back and forth throughout the cross'sectional peripheral path of the main tunnel and advancing the cutting tool longitudinally of the tunnel.

The invention resides in a method and a device for excavating cavities in the construction of extended subterranean structures, particularly tunnels, adits, and the like, which are built in the core method, characterized in that pilot tunnels are first driven within the proposed cross-section of the cavity to be excavated, that between these pilot tunnels partial cavities are excavated within which the tunnel linings (walls and roof) are poured in concrete with or without reinforcement and that the radial width of these corresponds approximately to the greatest thickness of the tunnel linings, and that finally the remaining core of earth between the tunnel linings is excavated.

In constructing a tunnel, for example, with an extended cross-section to accommodate a subway station, the conventional method is to first drive pilot tunnels within the area of the proposed tunnel walls or wall sections, to pour the walls or wall sections in concrete within the pilot tunnels in longitudinal stages, then to construct the usually semi-circular upper part of the cavity which remains above the upper edge of the walls. This is done by conventional tunneling methods, with a mole or other device, by pouring the roof lining and connecting it to the prebuilt walls and finally excavating the still remaining core of earth. The procedure is cumbersome, because the excavation of the upper part of the cross-section is very time-consuming and expensive. Furthermore, the still remaining core of earth has a small cross-sectional area in relation to the cross-sectional area of the tunnel walls, the roof, and sometimes the floor, because the pilot tunnel and the upper excava tion that is necessary for the construction of the roof take up a large part of the earth core.

The same holds true when another conventional method is used, when, for example, in addition to two lateral pilot tunnels running along the wall bases, a roof pilot tunnel is driven along the centre of the roof, when the earth between the roof pilot tunnel and the two lower lateral tunnels is removed and the wall and roof linings of the tunnel are poured in the form of halfshells. For this purpose, according to the conventional method, the partial excavations must be made by hand and may have to be shored. This, however, results in a considerably greater radial height than is necessary for the construction of wall and roof linings of the re quired thickness. This has the effect that at least an inner formwork must be built before wall and roof linings are poured. This is equally true for the previously mentioned conventional method. Furthermore, in this latter method, as well as in the previously mentioned one, the still remaining core of earth has a relatively small crosssection, and thus the whole purpose of the core method, which is to remove a core of earth as large as possible under the protection of the already poured wall and roof linings by using economical excavation equipment, is partly defeated. Another conventional system of constructing extensive subterranean cavities, for example, tunnels or bunkers, according to the core method also consists of making partial annular excavations from pilot tunnels for the construction of tunnel linings. These partial excavations correspond in width approximately to the width of the tunnel walls. However, in this conventional method, each of the excavations is dug separately from individual tunnels connecting the pilot tunnels. These are later filled with concrete.

In comparison with the prior art as demonstrated, it is the object of the invention to find a method of constructing extended subterranean structures, particularly of large cross-section, by first constructing pilot tunnels in a considerably simpler fashion and in shorter time, and to leave the still remaining core of earth as large as possible, so that it can be removed quickly and without danger with the aid of customary excavation equip ment, such as power shovels.

According to the invention, this problem can be solved by the initially mentioned method, in which partial annular excavations are made by a cutting device with at least one cutting tool. This cutting tool is mounted on a guide-frame that corresponds with the cross-section of the tunnel lining to be poured. The cutting tool is moved back and forth transverse to the tunnel axis from one pilot tunnel to the other. The guideframe is being moved forward along the axis of the tunnel, its lower end being guided within the two lateral pilot tunnels; it moves forward within the annular excavation with the cutting tool in front of it; subsequently the annular space is filled with concrete which is being placed from one of the pilot tunnels, while at the same time that part of the tunnel which falls within the pilot tunnels is also being poured. If necessary, reinforcing steel can also be installed.

The construction of wall and roof, or of tunnel linings, respectively, of an extended subterranean structure by this method offers several advantages compared with the conventional methods. Thus, the cutting device can be used in the construction of annular excavations of any cross-section, and if a cross-section has corners between pilot tunnels, it would only be necessary to round them off in order to facilitate the proper guidance of the cutting device. For the excavation of annular spaces with different cross-sections it is only necessary either to adjust the guide-frame to the appropriate cross-section or to exchange it. The cutting device which cuts out the annular space can be used for any type of cross-section. The tunnel linings can, therefore, also receive any desired shape, so that the tunnel can, for example, be built with a horseshoe-shaped cross-section. Furthermore, the cutting device and its drive can be of relatively simple construction, since the one or more cutting tools for cutting the annular spaces are only moved in transverse direction, and they are being moved within existing excavations formed by the pilot tunnels. In most cases, for example, in those cases when the thickness of the tunnel wall and roof linings is not too small and does not fall below the minimum necessary to operate the cutting tool or tools,

it is only necessary to excavate the annular space or spaces with a radial dimension that corresponds with the greatest thickness of the tunnel wall or roof linings required to withstand the earth pressure. In this, the outer, as well as the inner limits of the annular spaces form the corresponding limits of the tunnel linings to be built. If necessary, allowance can be made for waterproofing and/ or other insulation, and no formwork is required at all in the construction of the tunnel linings except for those parts which are within the pilot tunnels. In order to install waterproofing and/or other insulation, a seal or insulation sheet can be installed at the outer limit of the annular spaces. If necessary, the earth can also be sealed off at the inner limit of the annular spaces by a plastic sheet, in order to create a smooth inner surface for the tunnel linings to be poured. Since, as already mentioned, the annular spaces can be excavated with a cross-section that corresponds exactly with the shape and the greatest thickness of the tunnel lining, the remaining core of earth will also have the greatest possible crosssectional dimensions. This core of earth can be excavated shortly after the tunnel linings were poured, and the tunnel floor can be poured in stages.

According to another characteristic of the invention, provided that the earth material is reasonably stable, immediately after the excavation of the annular spaces has been completed, these partial annular spaces can be filled with concrete in longitudinal stages whose length will depend on the condition of the material to be excavated. If the material is not sufiiciently stable, it can be temporarily shored at the outer limit of the annular spaces, particularly in the overhanging area, by a movable shoring device which advances behind the guide-frame of the cutting device. Each of the longitudinal stages to be poured can be sealed off at their end by using an inflatable tube as a bulkhead.

Preferably, the method according to the invention is carried out in such a way that two annular spaces are first excavated in the conventional way from two lower lateral pilot tunnels and one central pilot roof tunnel, and that cast-in-place concrete is pumped into these spaces, to form the tunnel wall and roof linings, from the pilot roof tunnel. In this way, only a minimum of earth needs to be removed at this stage; thereby the removal of excavated material and also the placing of concrete into the annular spaces is made considerably easier.

The device to carry out the method can be constructed in a simple fashion as a guide-frame designed to correspond with the shape of the tunnel lining. It is set up across the longitudinal axis of the tunnel when the work begins. It carries a cutting tool that is movable transverse to the tunnel axis from one end of the frame to the other. The construction could be such that the one or more cutting tools are designed as a milling wheel whose periphery is studded with cutting-bits, or as an appropriate cutting-disc with an axis essentially parallel to the longitudinal direction of the tunnel. The cutting tool can be moved back and forth within the guide-frame through a cogwheel drive or through a cable line or chain drive.

A practical example of the invention is described with reference to the accompanying drawings, in which:

FIG. 1 is a cross-section of the proposed tunnel and the annular spaces to be excavated for it,

FIG. 2 shows the pertaining longitudinal section in the vicinity of the pilot roof tunnel, and I FIG. 3 shows an axial section of the guide-frame with a side view of a cutting tool.

FIG. 1 shows a proposed extended subterranean structure with an approximately horseshoe-shaped cross-section, whose tunnel linings consist of walls and roof and have a corresponding horseshoe-like cross-section. In order to construct this tunnel, at first three pilot tunnels 1, 2 and 3 are excavated in the conventional way, by using a mole or cutting machine which excavates a circular 4 cavity. If necessary, these pilot tunnels can have a support lining which is not shown in the drawing. From these pilot tunnels, as can be seen particularly Well on the right side of FIG. 1, two partial annular spaces 5 are excavated, and within these, the tunnel lining in the form of two halfshells is poured in concrete which may or may not be reinforced. (FIG. 1, left side).

According to the invention, the partial annular space 5 for the tunnel linings are excavated by a device which uses a guide-frame 4 which is curved in correspondence to the tunnel lining and is erected in a position where the tunnel begins (for example, within an exploratory shaft or at a vertical front wall at the foot of a slope). This guide-frame extends all the way from lower pilot tunnel 1 through roof tunnel 3 to the other lower pilot tunnel 2 and follows the shape of the proposed tunnel lining. On guide-frame 4 a cutting tool with at least one cutting wheel 7 moves across the axis of the proposed tunnel.

Cutting wheel 7, which turns on axis 8 parallel to the longitudinal direction of the tunnel has a diameter that corresponds to radial height 9 of the tunnel lining and is studded with cutting bits 10 on its periphery. In the version shown in the drawing, only one cutting wheel 7 is used, and it is movable from one end of guide-frame 4 in pilot tunnel 1 through pilot roof tunnel 3 to the other end of the guide-frame within the cross-section of the other lower pilot tunnel 2. Both lower pilot tunnels 1 and 2 are driven near wall base 11 of the proposed tunnel and contain guide-tracks 12 on which guide-frame 4 is moved forward in the longitudinal direction of the proposed tunnel, as indicated by arrow 13 in FIG. 2.

According to FIG. 3, axle 14 of cutting wheel 7 leads through gear case 15 which contains a pivot bearing (not shown) or through some other type of casing, and, in the version shown in the drawing, it is connected to motor 16, which is atached to the cutting wheel. The gear case (or casing) 15 on the other hand, is equipped with track wheels 17 on the inside and with roller 18 on the outside and is carried by track wheels 17 from one end of the guide-frame to the other, while cutting wheel 7, driven by motor 16, rotates around its axis 8 as indicated by the double arrow in FIG. 1 and moves back and forth in correspondence to the cross-section of the proposed tunnel lining. Roller 18 runs along the outer wall of annular space S. In order to enable the cutting tool to perform this lateral movement, it can be attached to a power-driven cogwheel 19 that runs on cogging 20 which, in turn, curves in correspondence to guide-frame 4 and also reaches from one end of the guide-frame to the other. The cutting wheel can also be driven instead by a cable line or by a chain drive.

When the cutting device is put into operation, cutting wheel 7 excavates partial annular spaces 5 which follow the cross-section of the tunnel linings and whose radial height 9 approximately corresponds only to the thickness of the proposed tunnel linings, in contrast to partial excavations made by conventional methods. The still remaining core of earth 22 which is excavated later has therefore maximum cross-sectional dimensions. Guide-frame 4 is moved forward in stages within partial annular spaces 5 in axial direction to the prosposed tunnel, according to the progress made in cutting, and is led along guide tracks 12 within the pilot tunnels.

Instead of only one cutting wheel 7, the cutting device can also be provided with two such wheels, each of which would excavate one of the two annular spaces 5, whose size and shape always corresponds to half-shell 6 of the tunnel lining to be poured. In this case, the two cutting wheels can be moved across the two half arches of guideframe 4 in such a way that their working range slightly overlaps in roof pilot tunnel 3. Each of the two half arches of guide-frame 4 can also be erected a short distance behind each other, so that their upper ends slightly overlap in roof pilot tunnel 3.

According to the invention, the partial annular spaces are continuously filled with concrete, which may or may not be reinforced, as the guide-frame with the cutting device advances, and in this way, half-shells 6, for example, the tunnel linings, are being constructed between the pilot tunnels. If, as in the version shown in the drawing, the thickness of half-shells 6 corresponds to radial height 9 of partial annular spaces 5, no formwork at all is required when the half-shells within the annular spaces are poured in concrete. If necessary, a waterproofing and/ or insulation sheet (not shown) can be installed at the outer limit of the annular spaces 5 in order to form a water proofing and/or insulation coat on the outer surface of the tunnel lining. In order to form a smooth inner surface for the concrete (or reinforced concrete) lining, the earth can also be covered with a plastic sheet on the inner wall of annular space 5. Formwork is 'only necessary within the cross-sectional area of pilot tunnels 1, 2 and 3 and can be built like the movable framework sections 23 and 24 shown on the left side of FIG. 1. In the example shown, concrete is placed by pumping it from roof pilot tunnel 3 with concrete pumps in such a way that each half-shell 6 is filled from its base upward. Halfshells 6, for example, the tunnel linings, are poured (as shown in FIG. 2), in longitudinal sections 25 whose ends are determined by earth conditions and to whose front ends an inflatable tube 26 can be connected to form a bulkhead.

If the earth material is not of sufiicient stability, it can be shored at the outer limit of partial annular space 5 in the conventional manner, by means of shoring device 27, which moves forward in the direction of the exca-vation behind guide-frame 4 and whose gradual movement can be controlled from the pilot tunnels.

What is claimed is:

1 In a method for excavating cavities in the construction of subterranean structures including the steps of driving pilot tunnels within the cross-section of a main tunnel to be excavated, excavating partial cavities between said pilot tunnels, forming main tunnel linings with poured concrete in said partial cavities, the radial width of said partial cavities corresponding to the greatest thickness of said linings, and removing the remaining core of earth between said linings, the improvement which comprises forming said partial cavities by moving a cutting tool back and forth throughout a cross-sectional path of said main tunnel in which said lining is to be formed while advancing said cutting tool longitudinally of said tunnel.

2. A method for excavating cavities as defined in claim 1, including the step offilling said paitial cavities with concrete immediately upon formation thereof.

3. A method for excavating cavities as defined in claim 1, wherein said pilot tunnels comprise two lower lateral tunnels and one central roof tunnel, and wherein said concrete is pumped into said partial cavities from said roof pilot tunnel.

4. A method for excavating cavities as defined in claim 1, including the step of sealing off longitudinal sections of said partial cavities by inflating an inflatable tubular bulkhead.

References Cited UNITED STATES PATENTS 1,292,159 1/1919 Trumpour 61--85 1,510,628 10/ 1924 Morgan 29933 X 2,466,709 4/1949 Karr 6185 2,979,318 4/1961 Haspert et al 299-15 FOREIGN PATENTS 461,564 10/1968 Switzerland 61-84 DENNIS L. TAYLOR, Primary Examiner 

